Lossy mode resonance optical fiber sensor to detect organic vapors

Trabajo presentado al 14th International Meeting on Chemical Sensors celebrado en Nuremberg (Alemania) del 20 al 23 de mayo de 2012.A transmission sensor able to detect Volatile Organic Compounds (VOCs) has been developed using optical fiber with Plastic Cladding (PCS). Specifically, 1.5 cm of the cladding was removed: along this section, polymer nanolayers were deposited by means of the Layer-by-Layer method (LbL). This structure was doped with an organometallic material sensitive to VOCs. In this manner, Lossy Mode Resonances (LMRs) were induced in the transmission spectra of the sensor showing a wavelength shift as the nano structure grown. The sensing material accelerated the LMRs appearance with respect to the nanolayers without additive reported in previous works, and also, its spectral shift. Once the construction process was completed, two LMRs were observed: the first one was located at 778 nm and the second one at 463 nm. In presence of ethanol vapors, the sensor spectrum varied, showing the first LMR peak a remarkable shift of 100 nm. This behavior is reversible and was also registered for isopropanol vapors. The sensor response was analyzed as well for different concentrations of ethanol vapors.The authors would like to acknowledge the financial support from the Spanish Ministerio de Educación y Ciencia through projects TEC2010-17805 and TEC2010-20224-C02-01.Peer Reviewe

Volatile organic compound optical fiber sensors: a review

Volatile organic compound (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chemical industries. Optical fiber VOC sensors offering new and interesting properties which overcame some of the inconveniences found on traditional gas sensors appeared over two decades ago. Thanks to its minimum invasive nature and the advantages that optical fiber offers such as light weight, passive nature, low attenuation and the possibility of multiplexing, among others, these sensors are a real alternative to electronic ones in electrically noisy environments where electronic sensors cannot operate correctly. In the present work, a classification of these devices has been made according to the sensing mechanism and taking also into account the sensing materials or the different methods of fabrication. In addition, some solutions already implemented for the detection of VOCs using optical fiber sensors will be described with detail.This work was supported by Spanish Ministerio de Ciencia y Tecnología and FEDER Research Grants CICYT-TIC 2003-000909 and CICYT-TEC 2004-05936-C02-01/MIC

Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

Sensor de fibra óptica para vapores orgánicos volátiles

Fecha de solicitud:22.12.2000.- Titulares: Consejo Superior de Investigaciones Científicas (CSIC).- Universidad Pública de Navarra- OTRI.[EN]The invention concerns the preparation and description of novel compounds behaving as materials sensitive to various analytes. Two synthetic routes leading to the preparation of the compounds with sensing properties have been tested successfully, although the first route is only valid for anionic L ligands. In the second, more general, route, one of the metallic centers of the double starting salt is eliminated and the sulfur centers are then coordinated. It can be used in the production of chemical sensors as components of the receiving system for the detection of small organic molecules in gaseous phase such as vapors of halogenated or aromatic solvents. Said property has been used in the design of a sensor that is based on fiber optics technology. [ES] La presente invención está relacionada con la preparación y descripción de nuevos compuestos que se comportan como materiales sensibles frente a diversos analitos. Se han probado con éxito dos rutas sintéticas que conducen a la obtención de los compuestos con propiedades sensoras, si bien la primera sólo es válida para ligandos L aniónicos. En la segunda ruta, más general, se elimina uno de los centros metálicos de la sal doble de partida para acometer luego la coordinación a los centros de azufre. Su utilización se puede incluir en el sector de la producción de sensores químicos, como componentes del sistema receptor, para la detección en fase gaseosa de pequeñas moléculas orgánicas, tales como vapores de disolventes halogenados o aromáticos. Esta propiedad se ha utilizado en el diseño de un sensor basado en tecnología de fibra óptica.Peer reviewe

Optimization of single mode fibre sensors to detect organic vapours

The construction of single mode optical fibre (SMF) sensors to handle with volatile organic compounds (VOCs), has been optimized to operate at the third telecommunication window (1550 nm). The main motivation is to take advantage of the photonic devices used in telecommunication systems that makes easier sensors multiplexing. Moreover, the low transmission attenuation at that wavelength offers the possibility of remote sensing. The sensing materials used suffer reversible structural alterations in the presence of VOC, such as colour change, which are detectable with a photonic system. Following the Electrostatic Self Assembly method (ESAm), a nanostructure is constructed onto cleaved ended SMF, which is doped with a sensing material. The fabrication of this type of sensors was focused on multimode fibres (MMF) and in the visible spectral range (VIS) so far. The implementation has been adapted to SMF and to operate around 1550 nm, specifically, by easing the adsorption of the VOCs molecules. It has been observed that the sensing material affects the morphology of the nanostructures as well and so, to the sensors response. The devices implemented show a potential use in the identification of single and complex mixtures of VOCs. © 2011 Elsevier B.V.The authors would like to acknowledge the financial support from the Spanish Ministerio de Educación y Ciencia through projects TEC2010-17805 and TEC2010-20224-C02-01.Peer Reviewe

Optical fiber sensors array to identify beverages by their odor

Four optical fiber sensors have been grouped in an array which is able to distinguish odors of different drinks. The sensing materials employed have been deposited onto optical fibers following the electrostatic self assembly method. The responses have been characterized in terms of reflected optical power; more specifically, the dynamic range and the recovery of each device have been used to discriminate between the samples. Data mining techniques based on the combination of principal component analysis and artificial neural networks are performed. The final system is trained to distinguish between grape juice, wine, and vinegar by using a set of one hundred samples of each one. Furthermore, the array can be located at up to 6 km away from the optical header, offering the possibility of in situ measurements.Peer reviewe